Tektronix 7T11A User manual

Part No. 070-6176-00
Product Group No. 42
7T11A
SAMPLING SWEEP UNIT
Please Check for
CHANGE INFORMATION
at the Rear of This Manual
First Printing JUN 1986
Revised SEP 1986
T ek t ron x
COMMTTTED TO EXCELLENCE
TEK
INSTRUCTION
MANUAL

Copyright ® 1986 Tektronix Inc. All rights reserved.
Contents of this publication may not be reproduced in any
form without the written permission of Tektronix Inc.
Products of Tektronix Inc. and its subsidiaries are covered
by U.S. and foreign patents and/or pending patents.
TEKTRONIX TEK SCOPE-MOBILE and are
registered trademarks of Tektronix Inc. TELEQUIPMENT
is a registered trademark of Tektronix U.K. Limited.
Printed in U.S.A. Specification and price change privileges
are reserved.
INSTRUMENT SERIAL NUMBERS
Each instrument has a serial number on a panel insert tag
or stamped on the chassis. The first number or letter
designates the country of manufacture. The last five digits
of the serial number are assigned sequentially and are
unique to each instrument. Those manufactured in the
United States have six unique digits. The country of
manufacture is identified as follows:
B000000 Tektronix Inc. Beaverton Oregon USA
100000 Tektronix Guernsey Ltd. Channel Islands
200000 Tektronix United Kingdom Ltd. London
300000 Sony/Tektronix Japan
700000 Tektronix Holland NV Heerenveen
The Netherlands

7T11A Instruct on Manual
TABLE OF CONTENTS
PAGE
LIST OF ILLUSTRATIONS ......................................................
LIST OF TABLES ........................................................................... v
OPERATORS SAFETY SUMMARY .................................... v
SERVICE SAFETY SUMMARY ............................................... v
SECTION 1 - SPECIFICATION
General Informat on .............................................................. 1-1
Instrument Features ............................................................ 1-1
Character st cs .................................................................... 1-1
SECTION 2 - OPERATING INSTRUCTIONS
General Informat on .............................................................. 2-1
Install ng the 7T1 1 A n the Osc lloscope ........................ 2-1
7T11A Hor zontal Ga n ....................................................... 2-1
TIME/DIV Readout .............................................................. 2-4
FRONT PANEL CONTROLS AND CONNECTORS .... 2-4
OPERATORS CHECKOUT PROCEDURE .......................... 2-4
General ................................................................................... 2-4
Before You Beg n ................................................................ 2-4
Test Equ pment Requ red .................................................. 2-4
Setup Procedure .................................................................. 2-5
Adjust ng SWEEP CAL ....................................................... 2-5
Observ ng a Fast R se Pulse ............................................. 2-6
DETAILED OPERATING INFORMATION ............................. 2-7
Tr gger ng Cons derat ons .................................................. 2-7
Tr gger ng Rate ..................................................................... 2-7
SWEEP RANGE Control .................................................... 2-8
TIME/DIV Sett ngs .............................................................. 2-8
TIME POSITION Control .................................................... 2-9
SCAN Control ..................................................................... 2-10
TRIG LEVEL and STABILITY Controls ...................... 2-10
Tr gger Pushbutton Sw tches ......................................... 2-11
PULSE OUT Connector .................................................. 2-11
Use of Real-T me Mode .................................................. 2-11
Use of a 50  Delay L ne ................................................ 2-11
Random Sampl ng .............................................................. 2-11
WARNING I
The rema nder of th s Table of Contents l sts the
serv c ng nstruct ons. These serv c ng nstruct ons
are for use by qual f ed personnel only. To avo d
electr cal shock, do not perform any serv c ng
other than that called out n the Operat ng Instruc 
t ons unless qual f ed to do so.
PAGE
SECTION 3 - THEORY OF OPERATION
Introduct on ......................................................................... 3-1
CIRCUIT THEORY ......................................................................... 3-1
REAL-TIME SAMPLING ........................................................ 3-1
General ................................................................................ 3-1
Sta rcase Ramp Output of the Hor zontal
Memory ................................................................................ 3-2
Lead T me Real-T me Sampl ng ................................... 3-3
Samples/D v s on Us ng Real-T me
Sampl ng ..................... 3-4
Summary of Real-T me Bas c Block
D agram ................................................................................ 3-4
Add t onal Real-T me C rcu ts ........................................ 3-5
Controls Affect ng T m ng and Delay .......................... 3-6
Important Waveform Relat onsh ps ............................... 3-7
SEQUENTIAL EQUIVALENT-TIME SAMPLING ......... 3-10
Add t onal C rcu ts Requ red ........................................ 3-10
Construct ng the D splay ............................................... 3-12
Waveform Relat onsh ps ............................................... 3-12
Factors Affect ng Dot Dens ty ...................................... 3-15
Blank ng .............................................................................. 3-15
Unavo dable Delay Introduced by the 7T1 1 A ......... 3-17
RANDOM EQUIVALENT-TIME SAMPLING ................ 3-17
Introduct on ....................................................................... 3-17
Random Mode Block D agram ................................... 3-18
Random Operat on ..................... 3-18
Waveform Relat onsh ps Dur ng Random
Sampl ng ........................................................................... 3-20
DETAILED CIRCUIT DESCRIPTION ...................................... 3-22
Introduct on ....................................................................... 3-22
Relat onsh ps Between the 7T11A and
Vert cal Un t .................................................................... 3-22
. TRIGGER INPUT .................................................................. 3-24
General .............................................................................. 3-24
Internal Tr gger ng ........................................................... 3-24
EXT 50 Q Tr gger ng ...................................................... 3-25
EXT 1 M Tr gger ng ...................................................... 3-25
HF Sync .............................................................................. 3-26
Tr gger Slope Ampl f er, SLOPE (-) or (+) ............ 3-28
Tr gger Ampl f er (TRIG AMP X1 , X10) ..................... 3-28
TRIGGER & HOLDOFF ...................................................... 3-29
Schm tt Tr gger ................................................................ 3-29
Holdoff Mult v brator (HOMV) ...................................... 3-30
Real-T me HOMV Sw tch ng ........................................ 3-31
Equ valent-T me HOMV Sw tch ng ............................ 3-33
Arm ng and Output Tunnel D odes ............................ 3-36
Output TD C rcu ts ......................................................... 3-36
TIME TO HEIGHT CONVERTER ...................................... 3-37
Start Mult v brator ........................................................... 3-37
TTH C rcu t ....................................................................... 3-38
i

7T11A Instruct on Manual
TABLE OF CONTENTS (CONT.)
PAGE
SLEWING RAMP & RT MULTIVIBRATOR ................... 3-41
Slew ng Ramp Generator ............................................. 3-42
Slew ng Ramp Comparator and
Strobe Dr vers .................................................................. 3-42
Real-T me Mult v brator .................................................. 3-43
RATEMETER ......................................................................... 3-43
General .............................................................................. 3-43
Pretr gger Comparator .................................................. 3-44
Tr ple Log Ramp ........................................ 3-44
Reset Mult v brator ......................................................... 3-44
T o Memory and T o Gate ............................................... 3-44
Start Correct on ................................................................ 3-45
HORIZONTAL AMPLIFIER .......................... 3-46
Ampl f er ......... .................................................................... 3-46
Hor zontal Memory Gate Dr ver ................................. 3-47
Hor zontal Memory and Gate .................. 3-47
SLOW RAMP GENERATOR & OUTPUT
AMPLIFIER ............................................................................. 3-48
Slow Ramp Generator - REP SCAN ........................ 3-48
Blank ng .............................................................................. 3-49
MAN and EXT INPUT SCAN ...................................... 3-50
Dot Pos t on Memory .................................................... 3-51
Output Ampl f er .............................................................. 3-51
SLOW RAMP INVERTER .................................................. 3-52
General ............................................................................. 3-52
T me Pos t on Ampl f er ........................................ 3-52
Slow Ramp Inverter ............................................... 3-52
TIMING SWITCHES .............................................................. 3-52
General .............................................................................. 3-53
Readout .............................................................................. 3-53
VOLTAGE DISTRIBUTION & DECOUPLING ................. 3-54
Real-T me and Equ valent-T me Log c ........................ 3-54
SECTION 4 - MAINTENANCE
PREVENTIVE MAINTENANCE .................................................. 4-1
CLEANING ................................................................................ 4-1
Exter or ................................................................................ 4-1
Inter or ................................................................................... 4-1
LUBRICATION ......................................................................... 4-1
VISUAL INSPECTION ........................................................... 4-1
SEMICONDUCTOR CHECKS ............................................. 4-1
PERIODIC ELECTRICAL ADJUSTMENT ........................ 4-1
TROUBLESHOOTING .................................................................. 4-2
TROUBLESHOOTING AIDS ............................................... 4-2
D agrams .............................................................................. 4-2
C rcu t Board Illustrat ons ............................................... 4-2
Adjustments and Test Po nt Locat ons ........................ 4-2
Stat c Sens t ve Dev ce Class f cat on .......................... 4-2
W r ng Color Code .............................................................. 4-3
PAGE
Res stor Color Code ........................................................ 4-3
Capac tor Mark ng. ............................ 4-3
D odes .............. 4-3
Sem conductor Lead Conf gurat on ............................... 4-3
Mult -P n Connector Ident f cat on ................................. 4-3
Interface Connector P n Locat ons ............................... 4-3
TROUBLESHOOTING TECHNIQUES ............................... 4-6
1. Check Control Sett ngs ............................................... 4-6
2. Check Assoc ated Test Equ pment .......................... 4-6
3. V sual Check ....................... 4-6
4. Check Instrument Adjustment ................................. 4-6
5. Isolate Trouble to a C rcu t ........................................ 4-6
6. Check Voltage and Waveforms ............................... 4-7
7. Check Ind v dual Components ................................ 4-7
8. Repa r and Readjust the C rcu t ................ 4-7
TROUBLESHOOTING PROCEDURE .............. 4-8
CORRECTIVE MAINTENANCE. ............................................. 4-10
OBTAINING REPLACEMENT PARTS ............................. 4-10
Standard Parts ................................................................ 4-10
Spec al Parts .................................................................... 4-10
Order ng Parts .................................................................. 4-10
SOLDERING TECHNIQUES ................................... 4-10
C rcu t Boards ............................................... 4-10
Metal Term nals ................................................. 4-11
COMPONENT REPLACEMENT ......................... 4-11
C rcu t Board Replacement ............................ 4-11
C rcu t Board P n Replacement ................................... 4-12
C rcu t Board P n Socket Replacement ................... 4-12
End-Lead P n Connector Replacement ..................... 4-12
Coax al End-Lead Connector Replacement ............ 4-12
Mult ple End-Lead Connector Replacement ...... 4-12
Tunnel D ode A3CR28 Replacement ......................... 4-13
Sw tch Replacement ................................ 4-13
Lamp Replacement ......................................................... 4-15
ADJUSTMENT AFTER REPAIR ...................................... 4-15
REPACKAGING FOR SHIPMENT .................................... 4-15
SECTION 5 - CHECKS AND ADJUSTMENT
PRELIMINARY INFORMATION ........................................... 5-1
Us ng These Procedures .................................................. 5-1
Part al Procedures ............................................................. 5-2
Performance Check Summary ...................................... 5-2
Adjustment Interval ........................................................... 5-4
Tektron x F eld Serv ce .................................................... 5-4
TEST EQUIPMENT REQUIRED ........................................ 5-4
Spec al F xtures .................................................................. 5-4
Test Equ pment Alternat ves .......................................... 5-4

7T11A Instruct on Manual
TABLE OF CONTENTS (CONT.)
PAGE
PART I - PERFORMANCE CHECK ........................................... 5-8
PERFORMANCE CHECK INDEX. ...................................... 5-8
PERFORMANCE CHECK POWER-UP
SEQUENCE .............................................................................. 5-8
A. SCAN AND TIMING ........................................................... 5-9
B. TRIGGERING ...................................................................... 5-14
PART II - PERFORMANCE CHECK AND
ADJUSTMENT ................................................................................ 5-24
PERFORMANCE CHECK AND ADJUSTMENT
INDEX ...................................................................................... 5-24
PERFORMANCE CHECK AND ADJUSTMENT
POWER-UP SEQUENCE .................................................... 5-25
PAGE
A. TRIGGER ADJUSTMENTS .......................................... 5-26
B. SCAN AND TIMING ......................................................... 5-31
C. TRIGGER OPERATION .................................................. 5-43
SECTION 6 - INSTRUMENT OPTIONS
SECTION 7 • REPLACEABLE ELECTRICAL PARTS LIST
SECTION 8 - DIAGRAMS AND CIRCUIT BOARD ILLUSTRATIONS
SECTION 9 - REPLACEABLE MECHANICAL PARTS LIST
LIST OF ILLUSTRATIONS
FIGURE
NO.
PAGE
FIGURE
NO. PAGE
7T11A Sampl ng Sweep Un t ...................................... ... v 3-2 7T11A complete block d agram for Real-t me
sampl ng ............................................................................
.. 3-3
1-1 Several plug- n conf gurat ons us ng the 7T11A
3-3
C rcu t waveforms at control sett ngs shown n
and a 7000-ser es osc lloscope ...................................
.. 1-2
F gure 3-1 ..........................................................................
.. 3-4
1-2 Plug- n conf gurat ons us ng the 7T1 1 A and a
3-4 T m ng relat onsh ps dur ng the f rst 1 /50th of
three-compartment 7000-ser es osc lloscope. ...
.. 1-3 one typ cal Real-t me sweep. 7T11A control
sett ngs as g ven n Agure 3-1 .................................... .. 3-5
2-1
Connector J641 (f xed shoe), prov d ng nter-
3-5 TTH ramp voltage versus t me at the three Real-
connect on between 7T11A and 7S11 for
t me pos t ons of the SWEEP RANGE control. ...
. . 3-7
strobe and tr gger s gnals .............................................
.. 2-1
3-6
Effect of the TIME POSITION and TIME/POSITION
2-2 Front-panel controls, connectors, and nd cators. .
.. 2-2 controls. SWEEP RANGE set at 5 ms/d v to
2-3
Equ pment setup for Operators Checkout
10 µs/d v pos t ons ..........................................................
.. 3-8
Procedure ..........................................................................
.. 2-4
3-7 Ideal Tr gger, Sweep, and HOMV waveform
2-4
Sequent al equ valent-t me sampl ng d splay of
relat onsh ps dur ng real-t me sampl ng .................... .. 3-9
1 µS, 1 V square-wave output of pulse generator. .. 2-5 3-8
S mpl f ed sequent al equ valent-t me block
2-5 Observ ng the lead ng edge of a fastr se pulse
d agram ..............................................................................
. 3-11
us ng the SEQUENTIAL equ valent-t me mode. .. .. 2-7
3-9 Ideal waveform relat onsh ps dur ng sequent al
2-6
Pos t on of selected TIME/DIV sett ng w th n equ valent-t me sampl ng ..............................................
. 3-13
control w ndow and correspond ng magn f cat on
3-10
Effect of turn ng TIME POSITION control fully
rate ......................................................................................
.. 2-9
clockw se on waveforms of F gure 3-9 ..................... . 3-14
2-7
Effect of TIME POSITION control (SWEEP
3-11
7T11A blank ng log c .....................................................
. 3-16
RANGE at 5 µs/d v to 10 ns/d v pos t on) ................
. 2-10
3-12 Unavo dable delay between tr gger po nt on nput
2-8 Real-t me sampl ng d splay of the 0.2 V, 1 kHz
s gnal and start of d splay w ndow ............................
. 3-17
output of a 7000-ser es osc lloscope cal brator. .. . 2-11
3-13 Effect of lead t me n mov ng d splay w ndow. ... . 3-18
3-14 Random mode block d agram ..................................... . 3-19
3-1
S mpl f ed block d agram of a sampl ng system
3-15
Ideal waveform relat onsh ps dur ng Random
us ng the 7T11A as a Real-t me sweep un t ...........
.. 3-2 equ valent-t me sampl ng ..............................................
. 3-21

7T11A Instruct on Manual
LIST OF ILLUSTRATIONS (CONT.)
FIGURE
NO. PAGE
3-16 D splay of samples taken n F gure 3-15 ................. 3-22
3- 17 Block d agram show ng nterconnect ons between
7T1 1 A and vert cal plug- n dur ng real-t me
operat on ................................................... 3-23
3-1 S Block d agram of the 7T1 1 A tr gger c rcu t ................... 3-25
3- 19 S mpl f ed 7T11A Tr gger Selector c rcu t
show ng use of r ght channel Sampl ng Un t as
source of nternal tr gger s gnal ........................................ 3-26
3-20 S mpl f ed d agram of HF SYNC c rcu t .......................... 3-27
3- 21 Relat onsh p of the output Tunnel D ode to
other 7T1 1 A c rcu ts ............................................................ 3-28
3-22 S mpl f ed schemat c of the Schm tt Tr gger
c rcu t ....................................................................................... 3-30
3-23 Operat ng character st cs of Schm tt Tr gger
c rcu t tunnel d ode (CR134). ................. 3-31
3- 24 Outputs of the HOMV and assoc ated c rcu ts. ... 3-32
3-25 Tr gger, Sweep, and HOMV waveform
relat onsh ps dur ng real-t me sampl ng ......................... 3-34
3- 26 Typ cal waveform relat onsh ps dur ng sequent al
equ valent-t me sampl ng ........................... 3-35
3-27 Tr gger output c rcu ts .......................................................... 3-37
3-28 Block d agram of c rcu ts shown on TIME TO
HEIGHT CONVERTER schemat c ................................. 3-39
3-29 Act ve port on of the TTH c rcu t when produc ng
a negat ve-go ng output ramp .......................................... 3-40
3-30 Equ valent c rcu t of M ller Integrator used to
generate TTH ramp ............................................................. 3-41
3-31 S mpl f ed block d agram of Ratemeter c rcu t ........... 3-42
3-32 Theoret cal change n voltage of Ratemeter Tr ple
Log Ramp capac tor (C414) w th charg ng t me. .. 3-44
3-33 S mpl f ed d agram show ng sources of Hor zontal
Ampl f er offset current ........................ 3-45
3-34 Slow Ramp Generator block d agram ............................. 3-49
3- 35 Inputs and outputs of the Slow Ramp Inverter. ... 3-50
4- 1 Res stor and capac tor color code ...................................... 4-4
4-2 Sem conductor lead conf gurat on ...................................... 4-5
4-3 Or entat on of mult -p n connectors .................................... 4-6
4-4 P n number ng on nterface connector ............................... 4-6
4-5 Exploded v ew of c rcu t-board p n and ferrule ......... 4-12
FIGURE
NO. PAGE
4- 6 Locat on of 200 MHz osc llator tunnel d ode
(A3CR28). ..................... 4-13
4- 7 M n mum range requ red for the 200 MHz
osc llator ................................................................................. 4-14
4-8 Connect ons to sw tch assembl es ................................... 4-16
4- 9 Connect ons to Interface assembly A4 ........................... 4-18
5- 1 Typ cal d splays for check ng t m ng accuracy ........... 5-11
5- 2 Sweep Out waveform to check Repet t ve
Scan rate ......................... 5-12
5-3 Determ ng d splay j tter ...................... 5-19
5-4 Typ cal d splay of the Pulse Out waveform ................ 5-22
5-5 Typ cal d splay of tr gger k ckout ...................................... 5-22
5- 6 Pos t on ng Tr gger c rcu t board for access to
nternal adjustments. ......................................................... 5-25
5-7 Typ cal d splay of Memory Gate blowby. .................... 5-33
5- 8 Typ cal d splay for adjust ng Slew ng Ramp
(A3R310) and Servo Zero (A1R588) ............................ 5-34
5- 9 Typ cal d splay for adjust ng Dot Pos t on
Memory (Al R645) and Servo Zero (AI R588) ........... 5-34
5-10 Typ cal d splays for check ng t m ng accuracy ........... 5-38
5-11 Sweep Out waveform to check Repet t ve
Scan rate. .......................... 5-39
5-12 Typ cal d splay for HF Sync adjustments ....................... 5-40
5-13 Determ n ng d splay j tter. . ............................................... 5-47
5-14 Typ cal d splay of the Pulse Out waveform ................... 5-51
5-15 Typ cal d splay of tr gger k ckout ...................................... 5-52
5-16 Tr gger ho ld off measurement. ......................................... 5-53
5-17 Typ cal d splay of strobe k ckback ................................... 5-53
8-1 Sem conductor lead conf gurat ons.
8-2 Locat on of c rcu t boards n the 7T1 1 A.
8-3 A3 — Tr gger c rcu t board assembly.
8-4 A2-T m ng c rcu t board assembly.
8-5 A1 - Log c c rcu t board assembly.
8-6 A4 — Interface c rcu t board assembly.
8-7 Locat on of Log c adjustments.
8-8 Locat on of T m ng adjustments.
8-9 Locat on of Tr gger adjustments.
v

7T11A Instruct on Manual
LIST OF TABLES
TABLE
NO. PAGE
1-1 Electr cal Character st cs ..................................................... 1-1
1- 2 Mechan cal Character st cs ................................................ 1-6
2- 1 M n mum Tr gger Holdoff ..................................................... 2-8
2- 2 Sweep Range and T me/D v Sett ngs ............................. 2-9
3- 1 Effect of TIME/DIV Control on Hor zontal
Ampl f er Ga n ............................................................... 3-XX46
3- 2 7T11A Readout Sw tch ng ............................................. 3-53
4- 1 Relat ve. Suscept b l ty to Damage from Stat c
D scharge ................................................................................ 4-2
4- 2 Power Supply W re Color Code ................................. 4-3
5- 1 Performance Check Summary ......................................... 5-3
5-2 Test Equ pment ..................................................................... 5-5
5-3 T m ng ................................................................................... 5-10
5-4 Low-Frequency Tr gger ng ................................................ 5-16
5-5 Med um-Frequency Tr gger ng ......................................... 5-16
5-6 H gh-Frequency Tr gger ng .............................................. 5-16
5-7 D splay J tter w th Opt mum Tr gger Cond t ons ... 5-20
5-8 T m ng ................................................................................... 5-37
5-9 Low-Frequency Tr gger ng ................................................ 5-45
5-10 Med um-Frequency Tr gger ng ......................................... 5-45
5-11 H gh-Frequency Tr gger ng .............................................. 5-45
5-12 D splay J tter w th Opt mum Tr gger Cond t ons ... 5-49
5-13 Tr gger Holdoff ...................................................................... 5-53

7T11A Instruct on Manual
OPERATORS SAFETY SUMMARY
The following general safety information applies to all operators and service personnel. Specific warnings and cautions will be
found throughout the manual where they apply and should be followed in each instance.
WARNING statements identify conditions or practices which could result in personal injury or loss of life.
CAUTION statements identify conditions or practices which could result in damage to the equipment or other property.
WARNIN G
GROUND THE INSTRUMENT
To reduce electrical-shock hazard, the ainfra e (oscilloscope) chassis ust be properly grounded. Refer to the
ainfra e anual for grounding infor ation.
DO NOT REMOVE INSTRUMENT COVERS
To avoid electric-shock hazard, operating personnel ust not re ove the protective instru ent covers. Co po 
nent replace ent and interna! adjust ents ust be ade by qualified service personnel only.
DO NOT OPERATE IN EXPLOSIVE ATMOSPHERE
7b avoid explosion, do not operate this instru ent in an explosive at osphere unless it has been certified for such
operation.
PREVENT INSTRUMENT DAMAGE
To prevent instru ent da age, plug-in units should not be installed or re oved without first turning off the
ainfra e power.
v

7T11A Instruct on Manual
SERVICE SAFETY SUMMARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
The following are safety precautions which appear in the service information sections of this manual. This Service Safety
Information is in addition to the Operators Safety Information given previously.
WARNING
DO NOT SERVICE ALONE
Do not atte pt internal service or adjust ent unless another person, capable of rendering first aid and resuscita 
tion, is present.
DISCONNECT INSTRUMENT POWER
To avoid electrical-shock hazard, disconnect the instru ent fro the power source before re oving protective
panels, soldering, or replacing co ponents.
AVOID EXCESSIVE MOISTURE
Circuit boards and co ponents ust be dry before applying power to prevent da age fro electrical arcing.
EXERCISE CARE WHEN SOLDERING
The Interface and Ti ing circuit boards are a ultilayer type with conductive paths la inated between the top and
botto board layers. All soldering on these boards should be done with care to prevent breaking connections to
the inner conductors. Only experienced aintenance personnel should atte pt repair of any circuit board.
USE PROPER CLEANING AGENTS
Avoid the use of che ical cleaning agents which ight da age the plastics used in this instru ent. Use a
nonresidue type of cleaner, preferably isopropyl alcohol, totally denatured ethyl alcohol, or a fluorinated solvent
(i.e., trifluorotrichloroethane), such as Freon TF cleaner or Spray-On #2002. Before using any other type of
cleaner, consult your Tektronix Service Center or representative.
DO NOT USE PIN SOCKETS FOR CONNECTION POINTS
The spring tension of the pin sockets ensures a good connection between the circuit board and the pin. This spring
tension can be destroyed by using the pin sockets as a connecting point for spring-loaded probe tips, alligator
clips, etc.
v

7T11A Instruct on Manual
7T11A Sampl ng Sweep Un t.
v

THE FOLLOWING SERVICING INSTRUCTIONS
ARE FOR USE BY QUALIFIED PERSONNEL
ONLY. TO AVOID PERSONAL INJURY, DO NOT
PERFORM ANY SERVICING OTHER THAN THAT
CONTAINED IN OPERATING INSTRUCTIONS
UNLESS YOU ARE QUALIFIED TO DO SO.
REFER TO OPERATORS SAFETY SUMMARY
AND SERVICE SAFETY SUMMARY PRIOR TO
PERFORMING ANY SERVICE.

Sect on 1-7T11A
SECTION 1
SPECIFICATION
General Informat on
The 7T1 1 A Sampling unit is designed for use in Tektronix
7000-series oscilloscopes. Several plug-in combinations in 
cluding a 7T11A are shown in Fig. 1-1. A 7S11 must be in
the compartment to the left of and adjacent to the com 
partment in which the 7T11A is operated. Therefore two
7T11A ’ s are not used in the same mainframe.
In Fig. 1-1 A the 7T11A is shown in the "A" Horizonal
compartment of the oscilloscope. The Vertical Mode and
Horizontal Mode pushbuttons providing useful presenta 
tions are designated for plug-in configurations A B and C.
For the configuration of Fig. 1-1 A four combinations are
shown. An alternate to the configuration shown in Fig. 1-2B
is with the ‘ LEFT' or ‘ B ’ or both of these mainframe com 
partments empty. Plug-in arrangements other than those
shown in Fig. 1-1 are possible.
Fig. 1-2 shows several plug-in combinations for three
compartment oscilloscopes. In these configurations the
7T1 1 A must be in the Horizontal plug-in compartment and a
7S11 must be in the Right Vertical compartment. Vertical
mode pushbuttons adding useful presentations are desig 
nated for each configuration.
The 7M1 1 may be used in any available mainframe com 
partment or operated out of the mainframe. For further in 
formation see the Operating Instructions section of this
manual under the heading of Detailed Operating
Information.
Instrument Features
The 7T1 1 A features a wide range of sweep rates using
real-time and equivalent-time sampling. Concentric switches
select the sweep range and time position range in different
combinations for the time/div desired. On equivalent time
ranges either sequential or random sampling is available.
Use of random sampling permits display of the leading edge
of fast-rise input signals without the use of a signal delay
line (such as the 7M1 1) or a pretrigger pulse from the signal
source.
Internal triggering or any of three modes of external trig 
gering can be selected by using the front panel pushbuttons.
A Schmitt trigger circuit is used except when HF SYNC is
selected. With EXT 50  input selected the Schmitt circuit
provides jitter free triggering from input trigger signals from
DC to 1 GHz. The display is free of trigger jitter or double
triggering even at low trigger repetition rates or when using
a square wave as the input trigger signal. A recovery time
control is not needed
Selecting EXT HF SYNC permits using frequencies of
1 GHz to approximately 12 GHz as the trigger input source.
With HF SYNC selected the signal connected to the TRIG
INPUT connector is routed to a built-in synchronizer thus
permitting X band signals to be viewed.
Excellent sweep linearity is provided when using the
7T11A. The timing circuitry in the 7T11A uses a time mea 
surement rather than a time programming process for hori 
zontal sample positioning on all equivalent-time sweep
ranges. During both Random and Sequential operation the
horizontal position of the dot on the screen is determined by
measuring the time interval between strobe and trigger. This
method results in improved timing linearity and a reduction
in display jitter. The accuracy of sweep timing and linearity
make it unnecessary during equivalent time sampling to
exclude the sweep start from accuracy specifications.
Character st cs
The following characteristics apply over an ambient tem 
perature range of 0 “ C to +50°C at altitudes up to 15 000
feet and after a five-minute warmup providing the instru 
ment was calibrated at a temperature between +20°C and
+30°C. During non-operation do not subject the 7T1 1 A to
altitudes above 50 000 feet or to temperatures below
— 55°C.
1-1

Spec f cat on — 7T11A
Plug-In
Conf gurat on
Ma nframe Sw tch ng
VERTICAL MODE HORIZONTAL MODE
Left R ght "A" "B"
7S11 7S11 7T11
7M11
7A-
7S11
7T11 7B - -
(B )
blank
7S11 7S11
7T11
(Cl
LEFT
ALT
ADD
CHOP
RIGHT
X
X
X
X
X
X
X
X
X
X
A
ALT
CHOP
B
X
X
X
X
X
X
X
X
X
X
6176-1
F gure 1-1. Several plug- n conf gurat ons us ng the 7T11A and a 7000 — ser es osc lloscope.
1-2
(A)

Spec f cat on — 7T1 1 A
TABLE 1-1
ELECTRICAL CHARACTERISTICS
Character st c
Performance Requ rement
SWEEP RATES
TIME/DIV
Calibrated from 5 ms/div to 10 ps/div selectable in a 1 2 5 sequence using
SWEEP RANGE and TIME/DIV controls.
Equivalent Time 5 µs/div to 10 ps/div using the 50 µs to 50 ns Time Position Ranges.
Accuracy
Within 3%.
Real Time 5 ms/div to .1 µs/div using the 50 ms to .5 ms Time Position Ranges.
Accuracy
On 50 ms TIME POS RNG
Within 3% beginning 250 µS after undelayed sweep start.
On 5 ms TIME POS RNG
Within 3% beginning 25 µS after undelayed sweep start.
On 0.5 ms TIME POS RNG Within 3% beginning 2.5 µs after undelayed sweep start or after 500 ns from start
of displayed portion of sweep. Does not include 100 ns/div and 200 ns/div positions.
VARIABLE (TIME/DIV)
Range Extends fastest sweep rate to at least 4 ps/div. Permits increasing the speed of all
sweep rates to at least 2.5 times the calibrated speed.
Pfug- n Conf gurat on
Left R ght Hor z
(A)
7S11
7S11
7T11A
Left
R ght Hor z
7 —
7S11
7T11A
(B)
Ma nframe Vert cal Modes
LEFT
ALT ADD
CHOP RIGHT
X
XX
X
LEFT ALT ADD
CHOP RIGHT
X
6176-2
F gure 1-2. Plug- n conf gurat ons us ng the 7T11A and a three-compartment 7000 — ser es osc lloscope.
1-3

Spec f cat on — 7T1 1 A
TABLE 1-1 (cont)
ELECTRICAL CHARACTERISTICS
Character st c Performance Requ rement
TRIGGERING
Input Resistance
EXT 50 
50  within 10%.
EXT 1 M
1 M within 5%.
EXT HF SYNC
1 M within 5%.
Sinewave Triggering
Internal
Sensitivity Range
X1 Trig Amp 125 mV to 1 V P-P at vertical input (5 kHz to 500 MHz).
X10 Trig Amp 12.5 mV to 1 V P-P at vertical input (5 kHz to 50 MHz).
•NOTE
Trigger circuits will operate to DC with pulse triggering, except for HF SYNC.
External
50  Input
Sensitivity Range
X1 Trig Amp 12.5 mV to 2 V (P-P) DC to 1 GHz.
X10 Trig Amp
1.25 mV to 2 V (P-P) 1 kHz to 50 MHz.
Safe Overload 2 V (DC + peak AC).
1 M Input
Sensitivity Range
X1 Trig Amp
12.5 mV to 2 V (P-P) DC to 100 MHz.
X10 Trig Amp 1.25 mV to 2 V (P-P) 1 kHz to 50 MHz.
Safe Overload
100 V DC or 100 V (P-P) to 1 kHz; derated 6 dB/octave above 1 kHz to 5 V (P-P).
HF SYNC Input
Sensitivity Range
10 mV to 500 mV (peak-peak) at 1 GHz; 200 mV to 500 mV (peak-peak) at
12.4 GHz.
Safe Overload
2 V (peak-peak).
Display Jitter
50  and 1 M Triggering
Sequential Mode
10 ps or less at fastest SWEEP RANGE position (fully CCW); 0.4 divisions or less at
remaining six positions of SWEEP RANGE; measurements made under optimum
trigger conditions.
1-4

Spec f cat on — 7T1 1 A
TABLE 1-1 (cont)
ELECTRICAL CHARACTERISTICS
Character st c
Performance Requ rement
TRIGGERING (cont)
Random Mode 30 ps or less at fastest SWEEP RANGE position (fully CCW); one division or less at
remaining six positions of SWEEP RANGE; measurements made under optimum
trigger conditions.
HF SYNC
Random or Sequential Mode 20 ps or less with a 12.4 GHz 200 mV (peak-peak) signal; measured under optimum
trigger conditions.
PULSE OUT (into 50 )
Amplitude
Positive-going pulse of at least 400 mV.
Risetime 2.5 ns or less.
Trigger Kickout ± 2 mV or less into 50  (except HF SYNC).
Minimum Trigger Rate in
RANDOM Mode 100 Hz.
SLOW RAMP GENERATOR
Scan Rate
REPETITIVE SCAN
Continuously variable from less than 2 sweeps/sec to at least 40 sweeps/sec.
HORIZONTAL DEFLECTION SYSTEM
Deflection Factor
SWEEP CAL Permits adjustment of deflection factor for all 7000-series mainframes.
EXTERNAL INPUT
Input Resistance
100 k within 10%.
Deflection Factor
Continuously variable from 10 V to 1 V/div.
Maximum Input Voltage
100 V (DC + peak AC).
SWEEP OUT
1 V/div within 2%.
Output Resistance
10 k within 1%.
1-5

Spec f cat on — 7T1 1 A
TABLE 1-2
MECHANICAL CHARACTERISTICS
Character st c
Performance Requ rement
Dimensions
Height
« 5 inches.
Width
» 2 3/4 inches.
Length (including front
panel knobs and rear
connector)
≈ 15 inches.
Construction
Aluminum alloy chassis with epoxy laminated circuit boards. Front panel is anodized
aluminum.
Accessories
An illustrated list of the accessories supplied with the 7T11A is at the end of the
Mechanical Parts List pullout pages.
1-6

Sect on 2-7T11A
SECTION 2
OPERATING INSTRUCTIONS
General Informat on
This section covers installation first time operation func 
tion of front panel controls and connectors and general op 
eration of the 7T11A Sampling Sweep Unit.
horizontal compartment and the 7S1 1 in the right-hand ver 
tical compartment. This provides an interconnecting path
between the 7T11A and the 7S11 for strobe and trigger
signals.
The 7T11A is intended for use in the Tektronix 7000-
series oscilloscopes. Use of the 7T11A with a 7S11 Sam 
pling Unit and any of a variety of S-series Sampling Heads
provides a sampling system adaptable to a wide range of
applications.
To insert the 7T11A into the oscilloscope compartment
align the grooves along the top and bottom of the plug-in
with the upper and lower slide rails in the oscillscope com 
partment. The unit slides straight in and self-locks itself in
place. The plug-in is removed by pulling straight out on the
plastic button labeled 7T11A.
Real-time sampling is provided at the three slowest
sweep rate settings of the 7T11A Sweep Range switch.
Sampling is in equivalent-time for the remaining four posi 
tions of the Sweep Range switch. On these four ranges
either sequential or random equivalent-time sampling may
be selected.
<5
The 7T1 1 A sweep may be synchronized using an internal
or external triggering source. External signals from DC up to
approximately 12 GHz can be used as the trigger source. A
trigger amplifier providing X10 amplification is available.
NOTE
Internal trigger signals are not routed through the trig 
ger source switches on the oscilloscope due to the
frequencies involved and noise considerations. Selec 
tion of the trigger source is ade on the front panel of
the plug-ins.
Triggering signals travel between plug-in units along 50 
coaxial or strip lines. These signals travel between plug-in
units using contacts on connector strips fastened to the
sides of the plug-ins. A connector strip is shown in Fig. 2-1.
Since the strobe pulses also travel between a 7T11A and
7S11 plug-in through contacts on the connector strips
these units must be located in adjacent oscilloscope
compartments.
Install ng the 7T11A n the Osc lloscope
The 7T11A is designed to drive the horizontal deflection
plates of the oscilloscope CRT and therefore is installed in
the right-hand compartment of a three-compartment oscillo 
scope. When only one 7T11A and one 7S11 are used in a
7000-series oscilloscope providing two vertical and two hor 
izontal compartments the 7T1 1 A is inserted in the left-hand
J641
6178-3
F gure 2-1. Connector <M41 (f xed shoe), prov d ng nterconnec 
t on between 7T11A end 7S11 for strobe and tr gger s gnals.
7T11A Hor zontal Ga n
The 7T11A horizontal gain must be matched to the hori 
zontal deflection factor of the CRT in the oscilloscope. Hori 
zontal gain is set using the Sweep Cal control (screwdriver
adjustment) located on the 7T1 1 A front panel. A method of
adjusting the Sweep Cal is discussed in the Operators
Checkout Procedure later in this section. This adjustment
must be reset each time the 7T11A is transferred between
oscilloscopes and when a considerable change in ambient
temperature occurs.
2-1

Operat ng Instruct ons — 7T11A
6176-4
F gure 2-2. Front-panel controls, connectors and nd cators.
2-2

Operat ng Instruct ons — 7T11A
TRIGGERING
SLOPE ( + ),(-) Pushbutton s — Selects th e pos t ve-go ng (+) or negat ve-go ng (-) slope of the tr gger ng s gnal.
STABILITY Control — Adjusts the w dth of the tr gger hysteres s. Also serve* a* a coarse sync adjustment n the HF SYNC mode.
TRIG LEVEL Control — Determ nes the ampl tude level on the tr gger ng waveform where tr gger ng s to occur. Also serves as a f ne synchron z ng
adjustment n the HF SYNC mode. The TRIG LEVEL control s concentr c w th the STABILITY control.
TRIG AMP Pushbuttons — Selects X1 or X10 ampl f cat on of the tr gger s gnal.
INT Pushbutton — Selects nternal tr gger ng for operat on w th sampl ng heads that prov de a tr gger p ckoff.
EXT 50 Q Pushbutton — Selects external, DC-coupled, low- mpedance tr gger operat on at the common tr gger nput connector.
EXT 1 MQ Pushbutton — Selects external, DC-coupled, h gh- mpedance tr gger operat on at the common tr gger nput connector.
EXT HF SYNC Pushbutton — Selects external, AC-coupled (1 M  to ground) HF SYNC operat on. In th s mode of tr gger operat on, the STABILITY
and TRIG LEVEL controls are used to obta n a stable d splay w th tr gger s gnals above approx mately 1 GHz.
EXT TRIG INPUT Connector — A 3 mm connector located near the lower r ght port on of th e front pan el and us e d for ntroduc ng an external
tr gger ng s gnal to th e 7T11A.
PULSE OUT Connector — A BSM connactor prov d ng a pos t ve puls e correspond ng to th* f r ng of th e tr gger c rcu t.
SCAN
External Input Jack — A p n jack ( nput res stance of 100 kQ) prov d ng an Input fac l ty for externally scann ng the d splay. W th the SCAN control
fully CW a one volt nput s needed tor each d v s on of d splay.
EXT INPUT Pushbutton — Allows scann ng the d splay us ng an external s gnal. In th s mode of operat on, the var able SCAN control serves as a
var able attenuator.
MAN Pu s hbutton — Provi des manual operation o f th e s can function u s ing th e variable SCAN con trol , D oes not function in th e three slowest ( re a l 
time} Sweep Ranges.
Var able SCAN Control — Prov de s an nternal voltage for adjust ng the scan rate n the REP mode, or for manually scann ng the d splay n the MAN
mode. Also used to set the hor zontal ga n us ng the SWEEP CAL control. Serves as a var able attenuator n the EXTERNAL INPUT mode.
REP Pushbutton — Prov des repet t ve scann ng of the d splay. Scan rat* s adjusted us ng the var able SCAN control. It doe s not funct on n the
three slowest (real-t me) Sweep Ranges.
SWEEP
SWEEP OUT Jack — P n jack prov d ng an output voltage proport onal to the d splay. W th an output res stance of 10 kQ, an output of one volt for
each d v s on of d splay s prov ded.
VARIABLE (CAL IN) Control — When n the out pos t on, rotat ng the VARIABLE control perm t* chang ng t me per d v s on from the cal brated value
selected by the TIME/DIV sw tch. Push knob n and release to act vate; the knob moves outward from th* TIME/DIV control when act vated.
SWEEP RANGE Sw tch — Selects the range of operat on of the TIME/DIV sw tch and nd cate* the correspond ng t me pos t on range (TIME POS
RNG). Perm t* a cho ce o f any of n ne TIME/DIV sett ng* at each of the seven pos t on* of the SWEEP RANGE SWITCH. The SWEEP RANGE control
s concentr c w th the TIME/DIV and VAR (CAL IN) controls.
TIME/DIV Sw tch — Select* cal brated t me/d v s on sett ng* from 10 ps/d v to 5 ms/d v, n 27 steps, n a 1, 2, 5 sequence.
TIME POS RNG — T me-pos t on ng ranges from 50 ns to 50 m s n seven decades are ava lable. T me-pos t on ng range ava lable and nd cated n
the TIME POS RNG w ndow s determ ned by the sett ng of the SWEEP RANGE sw tch. The nd cated range s always ten t mes the slowest
t me/d v of the Sweep Range selected.
POSITION Control — A front panel screwdr ver adjustment to pos t on the d splay hor zontally on the CRT of the osc lloscope.
SEQUENTIAL Pushbutton — Select* Sequent al Sampl ng mode of operat on. Doe s not funct on n the three slowest (real-t me) Sweep Ranges.
Perm ts equ valent-t me operat on at lower tr gger repet t on rates than does the Random mode.
RANDOM Pushbutton — Selects Random Sampl ng mode of operat on. Doe* not funct on n th* three slowest (real-t me) Sweep Ranges. Perm ts
the d splay of the nput s gnal pr or to the tr gger ng po nt w thout use of a delay l ne or pretr gger.
SWEEP CAL Control — A front panel screwdr ver adjustment that adjust* hor zontal ga n to match the osc lloscope deflect on factor. Adjusted
when sw tch ng 7T11A from one osc lloscope to another.
TIME POSITION Control — Perm ts cont nuously var able adjustment of delay n start ng the d splay, up to the amount nd cated n the TIME POS
RNG w ndow.
FINE Control — Ha* only about 1 % of the effect of the TIME POSITION control, and s part cularly useful at TIME/DIV sett ngs of h gh magn f cat on.
F gure 2-2. (cont). Front-panel controls, connectors and nd cators.
2-3